Silver halide photosensitive materials are generally prepared by coating a gelatin solution having dispersed therein the silver halide and other additives onto a support comprised of triacetylcellulose or poly(ethylene terephthalate), for example. The use of various coating promotors for uniformly coating the constituent layers in the preparation of such silver halide photosensitive materials is well known in the art. From among these coating promoters, anionic polymers such as poly(potassium styrenesulfonate), are often used in order to adjust the viscosity of the coating liquid.
For example, increasing the viscosity of a coating liquid by adding thereto polymers having anionic groups is disclosed, for example, in JP-A-49-115311, JP-A-51-81123, JP-A-52-67318, JP-A-53-39118, JP-A-53-39119, JP-A-57-105471, JP-A-61-203451, British Patents 676,459 and 1,539,866, and U.S. Pat. Nos. 3,022,172, 3,655,407, 3,705,798 and 3,811,897. (The term "JP-A" as used herein signifies an "unexamined published Japanese patent application".)
However, undesirable results frequently arise when these anionic polymers are used in layers which also contain polymers having cationic sites. For example, if an anionic polymer is added to a layer containing a cationic polymer for mordanting anti-halation dyes, the anionic polymer reacts with the cationic mordant, such that coating may become impractical as a result of aggregation, or the state of the coated surface may become adversely affected.
Furthermore, the anti-halation dyes may be released from the mordant by reaction with an anionic polymer. This results in the anti-halation dye being released from the anti-halation layer and diffusing into an adjacent emulsion layer. Adverse effects then occur such as a loss of photographic speed.
Suppressing aggregation with the mordant and achieving an effective increase in viscosity by using macromolecular copolymers of acrylamide and monomers which have --COOH groups (for example acrylic acid) as thickeners is disclosed in JP-B-49-21655 as a means of overcoming these problems. (The term "JP-B" as used herein signifies an "examined Japanese patent publication".)
However, thickeners of this type do not always have adequate viscosity increasing properties such that they must be used in large quantity. When thickeners of this type are added in large amount to layers containing gelatin and a polymer mordant, the adhesion at the boundary surface with the adjacent layer is often adversely affected.